Field of the Invention
The invention relates to novel drill-hole treatment agents which are fluid under normal conditions and have been composed by using an oil phase in combination. Referring to a characteristic example for treating agents of this kind, the invention is described hereinbelow by way of drilling fluids and drilling muds formed therewith. However, the field of application of the modification according to the invention of auxiliary liquids of the kind involved here is not limited thereto, while it also includes in particular the areas of spotting fluids, spacers, auxiliary liquids for workover stimulation and for fracturing.
Concerned by the invention are auxiliary liquids of the kind mentioned which are oil-based, i.e. which work using a continuous oil phase, as well as auxiliary agents wherein the oil phase has been emulsified in an especially aqueous continuous phase. Here, drilling fluids and drilling muds formed therewith are characteristic examples of the various possibilities.
There have been known, on the one hand, water-based drilling fluids having a content of from about 1 to 50% of emulsified oil phase--besides the other conventional auxiliary materials of such a drilling fluid--which are designated as emulsion fluids. On the other hand, there are being used to a wide extent in practice oil-based fluid systems wherein the oil constitutes the fluid phase or at least the predominant portion of the fluid phase. Here the so-called inverted drilling muds are of particular importance which, based on W/O emulsions, contain a dispersed aqueous phase in the continuous phase. The content of the dispersed aqueous phase usually is within the range of from about 5 to 50% by weight. The invention equally relates to both of the fields as mentioned here of the oil-based sweeping systems and of the water-based sweeping systems based on emulsions.
The use of the new fluid drilling-hole treatment agents is of particular importance for the exploitation of crude oil and natural gas, especially in the marine sector, while it is not limited thereto. The new systems may find general use in terrestrial drilling, for example in geothermal drilling, water drilling, in carrying out geo-scientific drilling and in drilling in the field of mining.